Assembly And Application Of Graphene/Silver Electrode Based On Direct Write Printing

Printing technology can not only realize the direct writing of accurate and complex patterns,but also provide a reference for the development of nano functional materials.Based on direct writing technology,the printing process is simple,convenient,low cost,green and environmentally friendly,which can effectively control the assembly of functional nano materials and facilitate the mass production of functional patterns and flexible electronic devices.In the printing process based on direct writing technology,the rheological properties of ink,the stability and precision control of pattern are the key to realize the functional pattern and flexible electronic devices.Graphene/silver composite has excellent physical and chemical properties.It is of great research value and scientific significance to study its assembly behavior in printing process,design three-dimensional structure and construct multifunctional electronic devices.Starting from the printing,assembly and application of nano materials,graphene oxide/silver nitrate direct writing ink was prepared to realize the application of graphene/silver materials in high conductivity flexible circuits,high sensitivity flexible sensors and other electronic devices.The main research contents are as follows:(1)Preparation of high conductivity graphene/silver circuits by direct writing printingFirstly,the Hummers,method was used to synthesize graphene oxide(GO),and the GO-Ag⁺ink suitable for direct writing technology was prepared.The line pattern of GO-Ag⁺ink was prepared by shear induction,and the flexible and highly conductive graphene/Ag(r GO-Ag)circuit was prepared by gas phase reduction.The influence of the mass ratio of graphene oxide and silver nitrate on the electrical conductivity and the influence of the ink concentration on the printed pattern were studied,and the properties and characteristics of the printed lines were characterized and analyzed.Experiments show that when the mass ratio of graphene oxide to silver nitrate is 1:3,the maximum conductivity of the composite material reaches 3.2×10⁵ S/m.The addition of silver nitrate can effectively increase the viscosity of the ink,and the printed circuit resolution can reach 200?m.The circuit shows good flexibility,the resistance of the circuit changes stably after 1000 cycles of bending.The brightness of the bulb has not changed significantly after the circuit is tested for bending,half-folding and twisting.Printing patterning is conducive to the construction of complex electronic devices,which has a good application prospect in energy storage,sensing,bionics and other fields.(2)Stretchable sensitive strain sensor based on three-dimensional porous graphene/silver structure.Three dimensional porous r GO-Ag structure was prepared by direct writing technique and freeze-drying gas-phase reduction.A simple physical compression three-dimensional porous r GO-Ag structure was combined with polydimethylsiloxane(PDMS)to prepare a tensile strain sensor.The effects of the different appearances of the three-dimensional porous r GO-Ag structure on the sensor performance,the influence of silver addition on the sensor performance,and the influence of the compressed structure on the sensor performance are studied,and the sensor is applied to the human body.Experiments have found that the performance of the sensor prepared when the ink concentration is60mg/ml is the most suitable.The addition of silver can effectively improve the sensitivity of the sensor,compress the porous r GO-Ag structure,and optimize the conductive network can effectively improve the performance of the sensor.The sensitivity of the sensor is 389.2 in the linear range of 0-81.7%strain,and the strain range is over 100%.The response time of the sensor is 83ms,which has remarkable durability and stability.The stretchable strain sensor can effectively detect human movement.Sensors based on the compressed porous r GO-Ag structure provide an attractive and promising solution for wearable devices involving a wide range of strains.(3)Pressure sensor based on three-dimensional porous graphene/silver structure.The three-dimensional porous r GO-Ag structure was prepared by direct writing technology supplemented by freeze-drying gas-phase reduction,and the pressure sensor was prepared by PDMS encapsulating the three-dimensional porous r GO-Ag structure.The performance of the pressure sensor is studied,and the sensor is used for biological monitoring.The pressure sensor prepared by the three-dimensional porous r GO-Ag structure has a sensitivity of 0.68 k Pa^-1,good electrical conductivity,significant compression sensitivity and excellent long-lasting stability.The r GO-Ag/PDMS nanocomposite material provides a new perspective for the design of three-dimensional macroscopic graphene,and opens up a new way to explore the wide application of multifunctional strain sensors under compression,bending,tension and torsion deformation.In a word,the ink system with Ag⁺is uniformly adsorbed on the go layer due to the electrostatic effect,and the ink with higher viscosity prepared at the same concentration of GO is more suitable for direct writing printing.Silver nanoparticles can effectively prevent the agglomeration of graphene and greatly improve the conductivity.A flexible and highly conductive graphene/silver circuit was fabricated by using shear force in direct writing printing to induce lamellar orientation and interface assembly.PDMS/r GO-Ag/PDMS sensor was prepared by PDMS encapsulation of three-dimensional porous r GO-Ag structure after compression of three-dimensional porous r GO-Ag structure by direct writing technology and freeze-drying gas-phase reduction.The intercalation of silver in graphene can effectively prevent the agglomeration of graphene,and the synergistic effect of silver nanoparticles and graphene can effectively improve the sensitivity of the sensor.